Technical Field
This invention relates to a clip-on type eyeglasses configured in such a manner that a clip-on attachment such as sunglasses is mounted to the front of the spectacle frame in a manner that allows it to be attached and detached freely to and from the spectacle frame.
Description of the Background Art
For a user in need of corrective eyeglasses and who also wishes to use sunglasses, a clip-on type sunglasses that can be attached to and detached freely from normal prescription glasses have also been in common use instead of prescription sunglasses. Some of such clip-on type sunglasses are configured in a manner that allows attachment and detachment thereof freely and is also configured with a flip-up system so that they can be removed from a user's field of view without the need of removing the clip-on attachment from the spectacle frame. Such sunglasses have an advantage in that use of these sunglasses can be temporarily interrupted when the user enters a dark place such as a room or a tunnel.
Japanese Utility Model Application Publication No. Sho 58-91721 (patent literature 1) discloses a prior art relating to the aforementioned clip-on type eyeglasses. This prior art discloses a clip-on member provided with a clip-shaped lens gripping member at the central portion of the clip-on member. The prior art of patent literature 1 is to grip and hold eyeglass lenses with or without eye rims, gripping clips and gripping poles provided to a chassis. These sunglasses can be configured in a manner that allows flipping-up thereof. Likewise, Japanese Utility Model Registration No. 3158051 (patent literature 2) further discloses a clip-type attachment member. The lens gripping member in the patent literature 2 has a pressure part that can be rotated in an angular range between a pressurized state where the pressure part is pressed against the back surfaces of eyeglass lens parts under a bias and an expanded state where the pressure part is rotated to be placed in a backward position. In the expanded state, upper edge portions of the eyeglass lens parts can be fitted in gaps formed between pressure strips of the lens pressure member and auxiliary lens parts. The eyeglass lens parts can be gripped elastically between the auxiliary lens parts and the pressure part.
The aforementioned prior arts do not provide an attractive appearance because the lens gripping member and its supporting mechanism, usually located at the center portion of the clip-on is too obtrusive. The gripping poles or the pressure part of the clip-on pinches the lenses of the spectacle frame while it is in contact with its lens surface. This may cause damages on the surface of the lenses in the spectacle side.
Various means of attaching the clip-on member to the spectacle frame have been suggested in addition to the aforementioned type that pinches and holds the lens surface, such as a clip-on member that grips the rim of the spectacle frame. Japanese Patent No. 4139379 (patent literature 3) discloses one such means. This means allows the clip-on to be held without making contact with the lens surface when the front clip-on member is attached to the spectacle frame. Patent literature 3 is for holding the clip-on member by gripping the rim of the spectacle frames or the edge of the lenses when the frame does not have rims.
As disclosed in the first embodiment case, in the patent literature 3 the clip-on member consists of a set of four clipping (metal wire material, for example) with strong elasticity which is formed into a V shape. Each tip of the clipping arms is bent to form hooking parts. In the configuration of patent literature 3, the clipping arms are engaged and held at four positions, including two upper positions and two lower positions.
As shown in FIG. 9 of patent literature 3, the clip-on member in this case is such that while the clipping arms are elastically pushed inward, the hooking parts of the lower clipping arms are hooked onto the back side of the eye rim or its equivalent part of the eyeglass frame, and is made to slide upward along the nasal area of the rim. At this time, the upper portion of the clip-on member is positioned diagonally in relation to the body of the spectacle frame. In order to hook the hooking parts of the upper clipping arms on the brow side of the eyeglasses, the left and right clipping arms with the hooking parts are pressed towards the eye rim. In this way, the inwardly pushed clipping arms try to restore to their original position, generating outward pressure towards the eye rims. This outward pressure ensures that the clip-on attachment is secured in place in conjunction with the upper arms clipped to the top side of the eye rim or its equivalent part of the eyeglass frame. The sunglasses of this embodiment can be removed from the eyeglasses by performing an operation reverse to the aforementioned operation.
While the clip-on member of patent literature 3 is held by gripping the aforementioned eye rims, the lens surface should preferably not be touched by the hooking parts of the clipping arms in order to prevent damages to the lenses caused by friction with any parts of the clip-on member. Lower left and right clipping arms create pressure towards opposite sides with regard to each other and thus gripping the eye rims. Thus, attachment of the clip-ons involves action of making the lower hooking parts slide upward along the inner nasal side of the eye rims or its equivalent part of the eyeglass frame. Depending on the size and shape of the eyeglass frame, the pressure for holding the clip-ons in place cannot be kept stable and may require some adjustment in size and shape of the lower pressing arms. In some cases, this makes the attachment of the clip-ons hard or difficult.
The conventional clip-on eyeglasses employing the clip type of patent literature 1 or 2 are relatively easy to attach and detach from the eyeglass frame. However, these clip-on type eyeglasses involve direct pressing or gripping of the eyeglass lenses which might cause damage to the lens surfaces. Additionally, the gripping force may weaken, causing the clip-on to move from its proper position. The conventional clip-on type eyeglasses of patent literature 3 involve sliding motion during attachment. Additionally, depending on the biasing force, the clip-on member may not be responsive to every size of eyeglasses.
The first problem to be solved by this invention is to provide a clip-on type eyeglasses that is easy to attach and detach to and from the eyeglass frame. This invention is also intended to provide a clip-on type eyeglasses that does not touch the lenses of the eyeglass frame, while making it possible to choose a detachable lower clipping arms so as to conform to the size of the eyeglass frame.